


aequum

by armethaumaturgy



Category: Undertale (Video Game)
Genre: Banter, Blood Kink, Blow Jobs, Bone Carving, Coming Untouched, Dusttale Sans (Undertale), Explicit Sexual Content, Killer Sans (Undertale) - Freeform, Killerdust - Freeform, Knives, M/M, Painplay, Subspace
Language: English
Status: Completed
Published: 2021-03-01
Updated: 2021-03-01
Packaged: 2021-03-13 13:40:50
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 2,038
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29776980
Author URL: https://archiveofourown.org/users/armethaumaturgy/pseuds/armethaumaturgy
Summary: "Better make it pretty," he scoffed, shoving his shorts down. He couldn't get them past his femurs, not with the way Killer sat on them, but that was fine. He didn't need much more exposed than what already was.Killer leered down at him, twirling the handle of the knife in a way that was definitely just for show. One of these days, he would cut himself and Dust would rupture his non-existent gut laughing at him."You forget who you're talking to."
Relationships: Sans/Sans (Undertale)
Comments: 10
Kudos: 88





	aequum

**Author's Note:**

> Dust has fucked up coping mechanisms, volume 2

The only light in the room was the dim lamp on the bedside table; Dust thought it wouldn't make for good working conditions, but what did he know? It reflected on the blade of the small knife Killer held, much too small to be one of the ones he used in battle.

No, this one was special, hooked and made for precision.

"Better make it pretty," he scoffed, shoving his shorts down. He couldn't get them past his femurs, not with the way Killer sat on them, but that was fine. He didn't need much more exposed than what already was.

Killer leered down at him, twirling the handle of the knife in a way that was definitely just for show. One of these days, he would cut himself and Dust would rupture his non-existent gut laughing at him.

"You forget who you're talking to."

"No, I really don't," he bit back. All he got for his trouble was a slide of the knife against the line of his iliac crest. It left a faint indent in the bone, nothing that would stand out among the multitude of other scars.

"Stay real still or I might just cut something you don't want me to," Killer warned, a threat in his voice that Dust deigned to ignore.

He did as instructed, though, mostly because he was curious. And a part of him was also excited, even if he'd never admit to it. Definitely not to Killer, at least. The guy's head was big enough as it was, no need to make it any more so. 

The first dig of the carving knife into the ala of his ilium caught him off guard. Killer, bless and curse him both, expected him to jerk, so he held him down with his other hand. He couldn't help a jab, though.

"I said stay still. Do I gotta tie you up for you to stop fucking moving?"

"Only if it's with a bow," Dust snorted. The next dig didn't startle him, and he relaxed into the mattress as his bone was chipped at. "A pretty one. Use your knife to make the ends all curly." Marrow pooled from the indent, and Killer wiped it off none too gently, phalanges catching on the cut. It almost made Dust hiss. Almost.

"Stars, does anything shut you up?" Killer huffed, but kept at it, chipping away a bit here, a bit there, at one point digging the knife so deep Dust thought he'd pierce the entire depth of the ala. 

"Yeah," Dust groaned, gritting his teeth. He wouldn't give Killer the satisfaction of crying out. "A big fat cock down my throat'll do it."

"Gross," was the response, "Maybe later."

"Who said yours was big or fat?"

"Watch it, dipshit." Killer drove the knife so deep Dust's eyelights sputtered out for a moment. Okay, _fuck,_ he deserved that one.

But truth be told, the flashes of pain were grounding like nothing else. As the deeper cuts were whittled along the edges, he thought he could fall asleep like that, with liquid fire dancing along his bones and the static from his marrow leaking down to stain the sheets. He wouldn't, because who the fuck knew what Killer would do to him, but the thought was there. It was easy to fall into a haze, though, staring at the ceiling and the shadows that danced along it as Killer's hand moved.

He refused to look down until Killer was done, half out of apprehension (nothing to kill the mood like an episode) and half out of not wanting to spoil the surprise. Killer didn't tell him what exactly he'd be carving into the bone, and Dust reasoned that if he didn't like it, it wouldn't be that big of a deal to heal it. Not like any leftover scars would be any news.

Killer hooked the knife after driving it into a new spot, and Dust only stayed still because his entire body locked up with the flash of white hot pain. It yanked, and there was a sickening crunch as a part of the ala was pried off. 

"Fuck," he gasped, hands fisting the sheets, "Dick."

Killer was grinning, jabbing at the edges much more carefully, and Dust settled down again. The process repeated; he lost count at eleven, but there had to be more pieces completely broken out. He knew mostly by the shards that dug into him where they fell to the mattress. At one point, Killer had procured a damp rag that he used to wipe the marrow away instead of using his fingers, but it didn't make it hurt any less so. The fabric was scratchy and caught on all the jagged edges that weren't smoothed out yet.

"Just details left," Killer told him, starting on those, apparently. The knife scraped off layers of the surface and spongy bone alike. "No need to be a bitch now."

Dust glared at him, and it took him a moment to realize Killer was calling him a bitch because he was crying. "Oh, fuck you," he grumbled, angrily wiping the lilac magic away with his sleeve. Stupid fucking physical reaction.

It didn't hurt enough to _truly_ hurt, even if his body seemed to think so. No, the fire along his joints was still as pleasant as it has been before, and the shocks of pain whenever his marrow was wiped away only made him sink further into the mattress and the pillows that propped him up. The rhythmical sound of the knife scraping against bone was nice, even if it was punctuated by wet splotches from time to time. That's when Killer always stopped for a second, to clean the area out. Apparently, the carving tool didn't like being wet.

The relative silence almost did lull Dust into a doze, but Killer dragged the now-bloody rag over the bone again, more thoroughly than before, and made a soft noise in the back of his throat, as if in contemplation.

"There. Done."

Dust looked down at himself, past the shirt that was more ruined by marrow spatters. The entirety of his left iliac wing was carved out, only the crest and outline left intact. Intricate vines intercrossed the ala, holes hollowed out between them to make it look almost like a lattice. There were a couple flowers carved along the vines, in bloom and coated in marrow so they almost looked painted.

It was... beautiful, for a lack of a better, and more snarky word. Killer really was good at what he did, and Dust found himself mesmerized, following along the carved lines as they twisted and wound around each other.

For once, he looked at himself and saw something pretty.

"I... don't hate it," he said, eventually, "Don't think I'll heal it." Killer's browbone, raised in expectation, moved further up as he barked out a laugh.

"Just fucking say thank you and get over it."

"Fuck you!" Dust propped himself up, testing to see if it hurt to move. Not more than he could handle. "Thanks."

Killer moved off of him and allowed him to sit up from the pool of marrow he'd left on the mattress. Not that he cared, this was Killer's bed. It was starting to dry, so he grabbed the rag Killer had been using and scrubbed at the pattern, wiping the crimson from between the small crevices.

"That blowjob still on the table?" Killer asked him, even as he stretched, his back popping with a loud, satisfying crack. Dust wasn't sure how long the entire thing took, but it couldn't have been comfortable to be hunched over the whole time. 

He shrugged, tossing the rag off somewhere for Killer to clean up later when he thought there was no fresh marrow seeping out. The carving was nice, so he reasoned Killer deserved a reward of some sort. "Why not?"

"Sweet."

A bit of shuffling around had Dust laying down on a clean side of the bed, the sheets feeling entirely too much as they dragged along the new edges of his pelvis (and fuck, that'd take time to get used to, wouldn't it?) and Killer sitting before him, shorts yanked down and off. Dust couldn't even blame him for already being summoned.

Instead of making fun of him, he opened his mouth and took the marrow-red magic in, tongue manifested so it could run over the length.

Killer arched up with a soft sound, and Dust was glad that skeletons didn't have a gag reflex, because it forced the entire length down his throat. He swallowed around it, feeling the precum leaking out of straight down. It splattered against the cloud of lilac gathering in his pelvic inlet, and that gave him pause. He pulled away, lapping along the underside of Killer's cock as he looked up.

"Will it fuck with my magic?" he asked, as it got hotter and yearned to manifest.

Killer cradled the back of his head, fingers bunching up the fabric of his hood, and urged him back down. Dust went, all the way back down, and swallowed around the length. "Nah," Killer said, voice strained with quiet huffs the more Dust stayed there, tongue flattened against the underside of his cock and throat conjured to provide more stimulation.

He decided to test the truth in Killer's self-assurance, and let his magic take its shape. The left side of his pelvis all but burned, magic chafing against the still-open wounds, but his ecto-body was intact and no different than usual. Killer, at the very least, made sure not to sever any leylines. 

His cock rubbed against the sheets, and there was a wet feeling that signified he'd bled over another part of the bed, but it provided sweet friction and he couldn't find it in himself to care. Killer's hand on his head held tight, and it only allowed him to bob the barest amount, but that didn't seem to bother the other skeleton.

Killer bucked up into him, hitting the back of his throat and leaking more precum straight into it. Once his other hand came to rest on the hood, too, and he started to move Dust's head to his liking, he briefly debated biting the ecto-flesh off. But he didn't.

Instead he let himself go lax and let Killer fuck his throat, sockets falling shut to enjoy the way all his senses were filled with the other's magic, like it was replacing the absence of Dust's usual thoughts.

His bones burned like they were set on fire, and it brought him to his peak all too soon, spilling under himself to add to the mess already there, without even being touched.

If his body was lax before, it was all but boneless after, and he barely remembered to swallow around the head of Killer's cock as it rammed itself as far as it could. Killer hissed out something above him, Dust's mind too muddled to properly place it, and then he was cumming, crimson magic spattering down Dust's throat to coat his ribcage.

There was no distinguishing what was marrow and what was magic painting his body, but it wasn't like Dust cared. He was pushed off once Killer rode out the aftershocks of his orgasm, and he fell to the mattress like a marionette with its strings cut.

His ribcage was heaving and he reeked of sex, sweat and marrow. He needed a shower. 

"Damn, you been practicing?" Killer laughed, and he sounded far away.

Dust had just about enough coherency left in him to scoff. "Not for you."

Killer made a mock-hurt sound, though it devolved into another chuckle. "I don't care who you practice for, I still get to enjoy it. Let me know if you want another carving, 'cuz damn."

Yeah, _damn._ With his ecto-body gone, the raw edges of his new adornment rubbed against the sheets again. Dust melted into the feeling and the weightlessness settling over him alike, sockets fluttering shut.

"Keep dreamin'," he mumbled.

Sleep overtook him, but his mental bet beforehand was in favor of waking up if not clean, then at least wiped down. And he didn't lose his mental bets often, after all.

**Author's Note:**

> my twitter is @esqers


End file.
